SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f75e48021b74dcdf254dabc2dd44a666aae0eeee5efeef6837b35a4d199b8cac' 
  AND token = 'IsGXKSPOQFKrysuXL2CY21TFReBHxRNiyzTeoPo7rt0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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