SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1356772c21987e5644041162dde2754fcd2f81cc84315435aafb2b2496d3032a' 
  AND token = 'XdxAhHLsdSW38bZgnTHw036NzzyJIH6v7O3aeg2FeHk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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