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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d25a150ac3d4a4b38edabcb739b4c7e36e61c8ca90310e4b8ea4d5ac55355a6' 
  AND token = '6BvIrUY0+AjCYQN6ihTlf3ZO18FY8ZDYoQblq9ivVpE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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