SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '93e36a8b2f061f0bd3a1ec532109ba08fe6ca50be2443330e8feadfac2790608' 
  AND token = 'vgJPptNhEVwahZRGE9OWb7vRmRKTYXToJSejGl6qdNw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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