SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '375d4e47b541a868f8577093c7ce8064eb2fa27b4ee33299032fa28fde080f48' 
  AND token = 'IL5PSzwN10G8OlFsjmJEbg0ietFWkkvsvpzCCKhDu0I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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