SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a379748401681cf58685774fbb4ecf1046986a9517c8870e1ac402cbc781f2d0' 
  AND token = 'VR+/wklPV6D+wWLB+Rwhay+WuHVU8yYIYfGStPxI3xg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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