SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40338b12a784aa29c655e4a80ad7a731d902e800c20c56f2dff4b3f3bceb3260' 
  AND token = 'sDP/FmtH4FNbrnAb8Lo+n1Yq+hZVJH5+1DaTC5uGVkg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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