SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '440de7e0c6cf26963753d468f42a1ea38e751e584cc7ee24df5b9cd59980b8ca' 
  AND token = 'gFnxq5Ib1bWJT1A4pInJSsMCCY+BWuEC9cPXIMSHhDM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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