SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'b0368a3b1ccd8020a14f8401ba438f8bcfd5a8d7560d96a1306d86b6efec560b' 
  AND token = 'T1mG5yECXkzCIIYuQkxNqPC0OV0IICirC0vDTnwGXRo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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