SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8bd15f86511ff30546a76c97e1ad700aaa47eb930e2c5b37f83ec8876450a4bc' 
  AND token = 't9gVFxxzEUzSJNDxzuA39jrBoi/MfgHl/+ghyG5zfn8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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