SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '681e624a731856b0b90f7fef61e2e09fcb2454d9c0fcd24defc6037b84b4c7cf' 
  AND token = 'S0rDDCjf39Wdsg/LCI8pzMEJ17FJvaKFdPGSRGXoeXo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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