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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff9df71af3d060fb0d6109555443e187044567900c76b511b600c83eb561e5d7' 
  AND token = 'ccolv9f/F00PdNB8ENQxmXP0qm9NhwYEw5TT3ChCEdk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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