SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bda1c4a2d1b2b285f8418e1bbf3099fe3e78671426d1d1683c30c71549ca0691' 
  AND token = 'JRjN0PbgLCxBwDhiXx34IgJeOz+3eQrgBDECylgnSb4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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