SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '848c82289298188ef0ca92af72433486a3a1d39c6102a34cc5cdb94da1d28db0' 
  AND token = 'AJGlhBaO92jZFgjjJ+VEflJlZpZN+IfBEYxcMdE7CgU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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