SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20ee9d36cfbdf3050da043fbf40d608815f0256638788fcd48e124b16b5d9f05' 
  AND token = 'fI2S1JJz2qzqwEW1Gc++qScR7AfUxKuAciMGnN1cY08=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00062

JSON explain

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