SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5544643d6aa298474ff86720e9add540b0a0a66e77c051262b85f28ea11c80c4' 
  AND token = 'hAaKpKSQAKBDwN75sluXVsFhpWOSlCusIh4uGBk9WOM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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