SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'afab1fed6464af50409879f5f21c868e1ba765d2d97642d8ca2b04d5951811f0' 
  AND token = 'ZYpQZ0mv693H13vzP+cycx2UYqhdkKnRuq6PGxwZy5Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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