SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '7769459b725cffd43e23dba07f46059210c7851d7118987ed2ab25b219b81d53' 
  AND token = '6tn4jBoqlSDRQdfgQ8QzSiT8Ef9j2KicuMPJWphLqng=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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