SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'd2682c6a882b1f8fd3dff74dc1b53309d49bd8a1b3a073b24aa5e9f0ccf13c66' 
  AND token = 'Rgt7TZKn0kiDpqix2Qg7GP++9WjwCKWlZXScfJWYY0s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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