SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ef688b898ccc9fd2f65875eed048e14fcb9f4efd82d598d01dc8319b96913ab4' 
  AND token = 'gmeVix4CjNZuNpdrzyJX+nImKDRVXGLh1janISECwrE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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