SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '2fb5334a46b93a2224914305b83593ed1ec3bee76e16883389c612b91c96c301' 
  AND token = 'qVzmiTgeRb1gtOTEyZx3uhh0AhlgkShlfWxasJSfFKg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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