SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '424accdfa715f519d22a51db5dc523e4625a3a2156f7a60c8cc0fb48aa6a21ad' 
  AND token = 'cd+wchVQm3ZETCjoPSbhol6omwM+c0scR5T+pevLO7Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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