SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f4b4276e6ee1549ced68f7a7ed9826e2971d7802e78f6281f531762532aa35b' 
  AND token = 'cIuXQPsdHs96agjfmWuRDVD6uI3aOI008Oo+yLxmkOI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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