SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad5bf4e2aa0caf95c528749edae7feea4e489899524d7d2a1ec6532a29408c58' 
  AND token = 'bO9Ggmvq5yf1bdK9L6WvdrWRpBgDLsQpo6794ifr7+k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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