SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e106f4ffbc0cde9789d178b49659d4bc13706b038017378ecfa17dc6002fd4f8' 
  AND token = 'xOCw2dLEmwusMQK/rQa9DygfXYZn+6kXSvBUKoyByWY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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