SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cdf87b803840fcb724b67f616e92501db8461f235ba72d49f90a506f48f1e0e2' 
  AND token = 'lFOZGUqbqKEvh87DC8yzgRLaQXobUdPDP+fcmOhPxdo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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