SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a02606e5fb078cc90f12820d90606194f6993f4d872169c483424be690398f3d' 
  AND token = 'zo0YTlpRoqxUzalAVJtKkF+QfOwLAVuDatZgpuligwQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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