SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c7bad006c6133652ed9a1ac6910d40cae97521ab965d215de8291761582f8d35' 
  AND token = 'Nw+By4R4idqH338DYbb2tlJS4fDg2oJY+hGuFKArGAY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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