SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d86b95796d898df4f2a01b71fe12e55e705720e2fa02df90e0ff8ee0a4f61cc' 
  AND token = 'f1FYdBszJ9qnE1xO8XYzkfxkgXAOrFMJ8taa6uefEsM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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