SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd146d2daaefb184601208f860a62f975a1ac6fa8b1a0a3108e4fdae78d2af542' 
  AND token = 'WdsDyzPwnEiIuyvFR2yIQh6MbmAI2lE50clkhqnN6ZE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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