SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2397c9355511194363f0b66aafaad86b0ea297d661fa991ab5754a6c9a63945a' 
  AND token = 'ISHST4nmcGf/CednabE2LIdd9RhmzKpsY+OLT7ZSMGA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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