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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7a7fea327913cb12f28a236f1d67dee3b839df9a65a36a53beddd1398c57cdb' 
  AND token = 'QQu+6l38TQSFxaLGIoeXTWB5Y6Ga33K2k4N5IHD2q94=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}