SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1da21d20c813c32a976da293edd1bec1687cb003fe23e8d619e6d9808bde5330' 
  AND token = 'JR45Gf3/1YnW0NoMI0RfJ9B1l5eR0XZNXYAiOcyl1cY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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