SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd200e8cce99c37ad6e62422aa5d64769874a41eed147ae6a309295d7671d4b77' 
  AND token = 'DZgu3tzOTIrqTjGTVts+GZYOcYGEbj7OfAcrYf/JqeY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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