SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf7913d70fb8ebccbb58fa95d218f17c79da1e16c7178550ac91292ab495f75f' 
  AND token = 'O6TWn9ZLJcuzgBjP2MxYC3VW18yEl5gkGXwBj1S3hiM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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