SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'dcecd91d5919fc0c4b6a1318294195c41dc9fd87e488b8900277a490a3fd40d0' 
  AND token = 'OnPZf1Lx+Kvq0WGpe1u4IAdo7x8Wh8HgvZVcKYzSvp8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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