SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5a116314b44270a565758d92ae877d4e089c63f9696c1307456e71c7c91759d' 
  AND token = 'IuuORdXzNe2taIniXjetH5TV7HGd+9oyIRIuGTnZiU4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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