SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e05edc10c70b985a89b31ae50bf70198c56f3d75aa23bd5959927314d6f99182' 
  AND token = 'exGW36OxdduRY1t89VyhxjGJ3i3f22afwhNNbcstiPg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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