SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'a9b96a1f4b4dd5eb39804bb0bb9462df921d480c5ea0d9bdfa7a374bccc7ea7e' 
  AND token = 'irjOsWdmP7AsxJwsSGLKDtvA4tsKF9VrDMkdEbR2dv8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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