SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4f9f882559c60fff80ab4f0476ae3de050b937521f9b3f49eca99fff7f55fe1' 
  AND token = 's+2jLX30xVzGgzPsNQRBUNGNvFiq1gqhLijIZEumyko=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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