SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ddec0ebef44fea837300ff3a7a8fc71f288cbe4d24628748d3903d3c9312816' 
  AND token = 'Xu4s/0kGeRBOBYzE2/SBmZikoxqmvAxTaxo43T+SvDk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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