SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '71192c8628bdd06a3f082b1d7549f4f0b8f82406d1b032faf7510f30c99b3b99' 
  AND token = 'qNrw+phjzftlOOlsOeGKaeZQaI0U1cXKKA4MC6ZgyNk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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