SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '258500887fed10c47f99c3c67c748c33b57239241ef10ce164a3248c7c7572ec' 
  AND token = '+X2tXk8yHaiB/R+8GWjw87UU1Kdjk4vxufYZw/Hn9wI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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