SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'f32b77d3fc40e3d58dc972c99a58c6ac4470dfcd49fced7c2c2fb5537b28ab79' 
  AND token = 'rD3WSxRnlP8kMHYm2XmpaOMw/xKfvGFEd6+Cy7UGGWg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}