SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89482336739e47a246b3524102af28f0dbcba9b862d5b3ef1ea3f5869bd14641' 
  AND token = 'XdNW2UTbmWOzZjMca6iHs4pLLb0fpak9HTY/K2jkBus=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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