SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e457c051077753a8cd631dde092e1568ac892cf056432d29beb8b8128c7ac82' 
  AND token = 'CfI8pW/E+1SNOGwplTbnDTkRDgQ3qzLd4lg6yG9J55I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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