SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a8e7c9a7b47ca0cac60639010ca92c87461026218169fb6e3d2113382cda876' 
  AND token = 'F3LgfOFo/VWx4M26VgJ7Uyqbw92z5qcTkbjud0j/B/k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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