SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '888d3eebf97fab90b37e46376525f4567f2b44ed635c330513ec50cf674146bc' 
  AND token = 'vnxzljbN2bId2ujL+c9Bpa6VLcItCNyuLx1Hiyh7GlQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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