SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '588a89932807fb0ab6e6a95ce5d54371f07fe62d3bc1cd89e985996590b18c55' 
  AND token = 'bVvzOYjHHHkm9RdWBP78pWalkJgymbXBjQ4s/naUc6w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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