SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '888a214b5f66ecec2b79f615cf755b937b791eb9c7dbea0e7a3580e608fc2eaa' 
  AND token = 'YXqrwWAA7StpwNOCHp+JtFcRImNR6EF7rUCzySOMFFU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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