SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '020b5fd4cf0e86bfa826d2d1851e0df57104a49e74e6c513e4ee61102e013950' 
  AND token = 'bvzWjvv0RtYdtFQT5Gcync7GnJgJfR06rvr49pAeopE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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