SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a79308a7b701b699e06b0468822ef445a58aa8b33f452ea31adb297e14e30674' 
  AND token = 'yti4Khnru3zcmbnYV08gRwIqKmK06xdTzaYEwdyniJQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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