SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f2b4553e03970e41d4523c24e3252903e6cea378936cb845f667afb5476f828' 
  AND token = '527COvaZ14pGWoznFPhHZN0boT+gHHvmvXsVa5ZHas0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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