SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'd0e83915e64fd0edc7ecb55b6169097344097d7029bf0511274bd9f6e14d9ee0' 
  AND token = 'u31cTq20pjILObjrLPqfbQpB9DRlTLHtNZ14hJDV3Zw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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