SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55a201732cff0bfccee5e07491de4029611306519a76918f72ab0309f71fc4f2' 
  AND token = 'DFWSCsYfSeFc1qmWe7uwIZPaMlQW7V6lNF8IDI2hAcQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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