SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df49e6ba36f4004de81bd8868a2a1e677b521ff77971a8346c654ff4dd7bd9b6' 
  AND token = 'SUZKS+V9eH9pIeWPB1gnGBJ/I0ZQmpPSOasXfULdHSA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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