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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42008ea690556d1ffcebd60a6b6abb6fb65c59e14d944664c45dedfc0c02fc00' 
  AND token = 'U85Xk5RZMoWmPY/cL5pGV1C/Rs8uLJOJ/7T6Fmzp6xk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}