SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '96703a1e5fcc6822bda70c8982a50f138d19dfc91549f9b16ab0abe8205fd0f8' 
  AND token = '1rzug5HGLeiN8PyEmEoDgYI1HFISesCA/17lUYf3lVw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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