SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c945f34ef0a596064917c66d6eee52f97b53fd099ab6a90b47ea1a73df202d52' 
  AND token = 'ZC2S4H7jZ4Ctty9vhzBESorU2ExkJyV1eDSbo5ceUtA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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