SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7661e55853af191779c4a7967fd00f828f466fb0a94653ced9d83f9f18e3fdca' 
  AND token = 'KSCMoNTw3swz1tVbq+629aXC9/doToR5gvjvJJN/OqM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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