SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14127ce4574988172b9eab03f32407888cfe29ae80bea224c39d383908908750' 
  AND token = 'i83RB3VODK0kg+RFk7NyVhzSetSl5UOc819vyuV7mHE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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