SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91855eb418c3a632717ab4711cd4b2add07a87c855aa303988b61014dab75375' 
  AND token = 'twUlBMwsrPk61+434G7Tz5EDfx/R19kGm+2YG9pdu2Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}