SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '88f4cbf67b181f5d1f9bf4298a563b35a707803f2abeaf5657de0d4db11b4838' 
  AND token = 'UmcD3D9SC/oDhZ11dA4wWGK/McmyUdQbp/RKdfgJaxY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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