SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '33f125390e713865df89e5c1ef591f4520a704385cd685243b670916898ce978' 
  AND token = '6ObJB8emxRMvNd24Pzjdu2tZGPiyZz5tcUMYhgnVdsQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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