SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5dcf93ef4dfda2569ccdd4d1cd83928f1c9f44183b4cc12ae34bebea0e4cacb1' 
  AND token = '36yxGRUgalvH16nqHLE603zBHFE3Ea2BT3dH0yquJrw=' 
  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"
    }
  }
}