SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6174d43bd32055d4e14701e499b4432fa62c0e91c26695287c9902b9a1f36073' 
  AND token = 'Hd1ndm97udtzp/HMvu7XUmfROLFh6sakrxAYu88+aLs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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