SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'e14cb93c0012522c021ebb2522fc4a464bc67b2807b134023c24ca57f8122a83' 
  AND token = 'vUc1LVl/b/j+X3nV9ZNzBKh7Z90rb5nJkm/0l8uGJrw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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