SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2bb4e6f9f6a3011ecf806bb403e6fe7ba58f83acb0d0372461236966d765ff99' 
  AND token = 'QO59s9Zt0HmivAxSYSdG+6aqdGnmwBP5PCCmyXoNArM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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