SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf8e8cba5be424cbfdad13177fd5b71d2277447a5be2da8fd271427d235041ce' 
  AND token = 'EW+FIMxSEAduT2loUFYAqlozXMK6PIGgcGsHn9EqhAs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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