SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf9f1381c850fc2d1f790c06b063ae9c13ff6c3cb5c77b0b8d50d7964510de21' 
  AND token = 'xHwDUxbYk5D6q91T33h/XO5st5xR0BCGnoXUxdaz+HQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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