SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '11d0bd4d64a749173e109942a83ff2bef270229bd794b0b5e38a36ba505610f1' 
  AND token = '1+ZXiCJ+Kzd9h7A3MMBYA2s6XSt/xPBg0XoJn0aHgZQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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