SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31543f687110b69f83991f4ccea6c87c9581ca1eb7e9f25ce101d578a89a7626' 
  AND token = 'oCoZSAewkBnuOdGzBrMWvacUVUTqwEtxlpssIyheqTk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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