SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2dc2484dd1262eaba62da45eb323f40051f3adbb08a9b8284b90e5c1483c62e6' 
  AND token = 'ENvS/aCGne1ENTBy1HJmztW76cXpZF1rEiX6esxawUc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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