SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3d391832ce27bfcff833cc105dfb5bbed6ceaf47419a58baa8f25c093d1d5bf' 
  AND token = 'UsuwNWmGxhSCxcjFXAVJB2NKWMPHPjzxdUY2Sm/QcAw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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