SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'c57f4e5ec38aafabd516e38e763699a145ad5b5ee90ffad50992ca61468e8649' 
  AND token = 'O7Cev6XEhGJhg52uSgSCR58azOcruXG6WuFFqMrIlqQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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