SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '238ad8d3b649d076647e2874d9bc9acf147e97d2a33dce9368b63fe6ea0f1bab' 
  AND token = 'Yb/Rw5yK/SlI+f8JKdC76HJXqLbHnhc5H5POzIFFdvw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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