SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd961a93791a5b3a4b5bc4ebede4966788d7f1bda1c25692e210961b828da5b9' 
  AND token = 'mfRoly6PylHdasXgER66O6aq08XDyYA10o/PlqbOKgs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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